fugitive
you can harbor a fugitive
noun
a person who has escaped from a place or is in hiding, especially to avoid arrest or persecution:
«…からの» 逃亡者; 避難者, 亡命者 «from»
e.g. fugitives from justice
e.g. as modifier : fugitive criminals.
as modifier quick to disappear; fleeting:
｟かたく｠ 長くもたない, はかない; 一時的な; ふらふらした
e.g. he entertained a fugitive idea that Barbara needed him.
ORIGIN
late Middle English: from Old French fugitif, -ive, from Latin fugitivus, from fugere ‘flee’.